As shown in FIG. 1a, a hard disk drive 5 conventionally includes at least one rotating data storage disk 45. Frequently, but not necessarily, a plurality of disks 45 is mounted on a common rotating spindle 9 to which rotational force is imparted by a suitable spindle motor 13. Each data storage disk 45 is provided with an associated transducer carrying slider 29 which "flies" in close proximity to the rotating data storage surface in accordance with so-called "Winchester" technology so as to write data to the surface and read data previously written to the surface. As shown in FIG. 1b, each slider 29 makes point contact to the load beam 20 by a load dimple 19, the combination of which makes a gimbal assembly forming part of a rotary actuator assembly which positions the suspension over the rotating disk.
As shown in FIG. 2, a load beam 20 typically includes a swaging boss 22 which is in turn attached by conventional ball-swaging to an actuator E-block. The load beam 20 also includes a spring section 23 and a relative rigid section. The rigid section may have longitudinal side rails. The stiffening side rails may be formed either away from the slider 29, as shown in FIG. 2, as "up-rails" 24, or towards the slider 29, as shown in FIG. 3, as "down-rails" 28. Typically, rails are approximately 0.2-0.3 millimeters in height. One exemplary down-rail load beam design is disclosed and characterized in commonly assigned U.S. Pat. No. 5,027,241 to Hatch et al., entitled, "Data Head Load Beam for Height Compacted, Low Power Fixed Head and Disk Assembly".
Each load beam 20 projects between a pair of data storage disks 45, as shown in FIG. 1, and positions the slider 29 at predefined concentric data tracks on each disk surface. During operation, the rotary actuator assembly positions the slider 29 at a substantially constant distance away from the disk surface, commonly referred to as the "flying height". A preload force formed into the load beam 20 and coinciding at the load dimple 19 biases the slider 29 towards the disk surface and against an aerodynamic "lifting" force generated by the spinning disk to maintain a relatively constant flying height. When the disk drive is not in operation, the rotary actuator assembly typically moves the slider 29 to a "parked" position at a landing zone, relatively adjacent the spindle. Alternatively, the rotary actuator assembly may move the load beam from a position between the disks 45 to a radial location beyond the edge of the disks 45 onto a parking ramp (not shown), located radially adjacent the edge of the disk 45.
Disk drives are designed to withstand the shock forces which are usually encountered in a normal operational environment, but when being handled or moved, shock forces from bumping and dropping, in the absence of suitable restraints, may result in damaging displacement and/or collisions of the structural parts. One example is "head slap", wherein the slider is displaced away from the disk surface, causing the slider to detrimentally collide with the disk.
In seeking to make disk drives more resilient to shock force damage, disk drive manufacturers have looked to various designs and means to limit or eliminate such damages. For example, U.S. Pat. No. 5,239,431 discloses a device for limiting slider displacement from a disk surface by extending a annular flange around a disk spacer, over the parking zone. An illustration of a flanged spacer 14a is shown in FIG. 1a. Also shown is a flanged disk clamp 12 and a flanged motor hub 15.
The drawback of these flanged spacers is that tolerances introduced during the manufacturing and assembly of the drive cause vertical misalignment ("stack-up") between the disks and the actuator E-block arms. Stack-up commonly leads to collision and interference between the load beam and flange. The inventors of the present invention have found that a nominal clearance of approximately at least 0.20 mm. between the flange and load beam is required to sufficiently avoid interference and collision thereabout. A nominal clearance j, between an up rail 24 of load beam 20 and flange 12a is represented in FIG. 4a. FIG. 5a, similarly, shows a nominal clearance k between a down rail 28 and flange 12b. However, with manufacturing and assembly tolerances and vertical misalignments, clearance is reduced to j' and k', and in a worst case, can result in contact between the load beam and the flange, as illustrated in FIGS. 4b and 5b. Such collisions may produce debris, possibly resulting in catastrophic failure of the head/disk interface. Given the capabilities of conventional manufacturing methods, in order to maintain adequate clearance between the load beam and flange, allowable tolerances would be practically unrealizable.
Thus, a hitherto unsolved need has remained for a load beam having features which limit displacement of the slider from the disk while compensating for manufacturing and assembly tolerances so as not to create collisions/interference between the load beam and flanged disk spacers.